Replace ProtoFileSourceGenerator and WriteProtoFileTask with a new
GenerateProtoFileTask that creates its own Roslyn compilation. This
solves the timing issue where source generators run too late for
Grpc.Tools to process the generated proto files.
The new task runs after ResolveAssemblyReferences but before
_gRPC_GetProtoc and CoreCompile, ensuring the proto file exists
when Grpc.Tools needs it.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
The WriteProtoFileTask now receives RootNamespace and AssemblyName from
MSBuild and uses them for the placeholder proto's csharp_namespace instead
of hardcoded "Generated.Grpc". This ensures GrpcGenerator can find the
service base types on first build, enabling gRPC service registration
to work without requiring a second build.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
